DE102019109183A1 - Method for manufacturing a hollow shaft - Google Patents

Abstract

The invention relates to a method for producing a hollow shaft from a tubular preform by spinning, whereby both ends of the preform are each formed with at least one forming roller, using a tubular preform (1) with any cross-section and the preform (1) during the entire manufacturing process is held on a workpiece holder (2) up to the finished hollow shaft in the central pipe area (1a).

Description

The invention relates to a method for producing a hollow shaft from a tubular preform by spinning, wherein both ends of the preform are each formed with at least one forming roller.

Such a procedure is over DE 103 37 929 A1 known. This document describes a process for the production of one-piece hollow bodies with profiled end regions from a preform with a circular tube cross-section, the preform being initially stretched in its central region in a first process step. After completion of this ironing step, the preform is inserted into another workpiece holder and then at least one end area is ironed in a second method step and this end area is further processed in a third method step if necessary.

This known method is relatively complex, however, since it is necessary to carry out the various process steps to hold the preform or the partially already formed preform one after the other in different workpiece holders, so that a continuous forming process is not possible. In addition, when changing the workpiece holder, a complex adjustment is necessary in order to ensure an exact concentricity of the preform with the forming rollers. Furthermore, the method is limited to tubular preforms which can be ironed by spinning.

The object of the invention is to further develop such a method in such a way that it enables a continuous process sequence and can be used universally.

This object is achieved according to the invention in a method of the type specified in that a tubular preform with any cross section is used and the preform is held by a workpiece holder during the entire manufacturing process up to the finished hollow shaft in the central pipe area.

The method makes it possible to carry out the entire forming process with just one workpiece holder, so that the entire forming process can run continuously. This also eliminates the need for additional adjustments that would be required when changing the workpiece holder. In addition, it is possible to use tubular preforms with any cross section, i.e. not just circular preforms, so that the hollow shaft produced in this way is suitable for various purposes, e.g. for holding winding packages in an electric motor. During the respective deformation, the preform is set in rotary motion relative to the at least one deformation roller, for which purpose the workpiece holder with the preform and / or the at least one deformation roller is driven.

It is particularly preferred that a tubular preform with a polygonal cross section is used. In principle, any polygonal shapes are possible. During the reshaping, the polygonal cross-section in the central tube area, which is held by the workpiece holder, remains unchanged, while only the end areas are reshaped in a rotationally symmetrical manner.

Both drawn and welded tubes can be used as preforms.

In a particularly preferred embodiment it is provided that the two ends of the preform are at least partially reshaped at the same time. On the one hand, this shortens the forming time and, on the other hand, results in a torque neutralization in the middle of the tube.

Depending on the requirements for the finished hollow shaft, it is preferably provided that at least one end is stepped one or more times, i.e. axially adjoining areas with different diameters are generated.

Furthermore, it is advantageously provided that an outer and / or inner profile is introduced into at least one end.

It is further provided that before the introduction of the outer and / or inner profiling into the at least one end, a possibly profiled inner mandrel is axially inserted.

If the finished hollow shaft is to have an outer or inner profile at both ends, provision is accordingly made for an inner mandrel to be inserted into each end. At least one correspondingly profiled forming roller and a non-profiled inner mandrel are used to introduce an outer profile, and at least one non-profiled forming roller and a profiled inner mandrel are used to introduce an inner profile.

It can very particularly preferably be provided that the two inner mandrels are connected to one another in a force-locking and / or form-locking manner at the end. The front ends of the two inner mandrels can e.g. have a spur toothing and are axially pressed against each other and thereby locked, so that lateral radial forces can be absorbed.

Finally, it is advantageously provided that the deformation takes place at least temporarily Heat application takes place. The heat can be generated inductively, for example, and hardening of the component can be achieved at the same time through this application of heat.

• 1 einen Längsschnitt durch eine rohrförmige Vorform,
• 2 einen Schnitt gemäß der Linie A-A in 1 mit drei verschiedenen Ausführungsformen,
• 3 eine perspektivische Darstellung der in einem mittleren Rohrbereich von einem Werkstückhalter gehaltenen Vorform während der Umformung,
• 4 eine Seitenansicht der 3, teilweise im Längsschnitt,
• 5 einen Längsschnitt durch eine fertige Hohlwelle,
• 6 ein Detail X in 5,
• 7 ein Detail Y in 5,
• 8 einen Längsschnitt durch eine Hohlwelle während der Umformung unter Verwendung zweier geteilter Innendorne,
• 9 eine Abwandlung der 8 mit zwei in Axialrichtung formschlüssig miteinander verbundenen Innendornen,
• 10 eine perspektivische Darstellung der beiden Innendorne nach 9,
• 11 einen Endbereich einer Vorform mit einer eine radiale und axiale Kraft aufbringenden Umformrolle und
• 12 eine perspektivische Darstellung der 11.

The invention is explained in more detail below with reference to the drawing. These show in

• 1 a longitudinal section through a tubular preform,
• 2 a section along the line AA in 1 with three different designs,
• 3 a perspective view of the preform held in a central tube area by a workpiece holder during the forming process,
• 4th a side view of the 3 , partly in longitudinal section,
• 5 a longitudinal section through a finished hollow shaft,
• 6th a detail X in 5 ,
• 7th a detail Y in 5 ,
• 8th a longitudinal section through a hollow shaft during forming using two split inner mandrels,
• 9 a modification of the 8th with two inner mandrels positively interconnected in the axial direction,
• 10 a perspective view of the two inner mandrels 9 ,
• 11 an end region of a preform with a forming roller which applies a radial and axial force and
• 12 a perspective view of the 11 .

A tubular preform is in 1 generally designated 1. This tubular preform 1 can be a drawn or welded tube made of metal. It is essential for the invention that the tubular preform can have any cross section.

In 2 is indicated by way of example that it can have a circular, square or triangular cross section. In general, any cross-sectional shapes, preferably polygonal cross-sectional shapes, are possible in adaptation to the respective application.

Since in the method according to the invention, the middle pipe area 1a the tubular preform 1 is not reshaped, this area is suitable, for example, without further processing to accommodate winding stacks of an electric motor or the like.

To get out of the tubular preform 1 To produce a hollow shaft by spinning, it is essential to the invention that the tubular preform 1 over the entire manufacturing process up to the finished hollow shaft in its central tube area 1a from a workpiece holder 2 is held. This split, ring-shaped workpiece holder 2 accordingly has an inner contour that corresponds to the outer contour of the tubular preform 1 corresponds.

Because the preform 1 from the workpiece holder during the entire manufacturing process 2 in their middle area 1a is held, the entire process can be carried out continuously without changing to another workpiece holder.

It is preferably provided that the two ends 1b and 1c the preform 1 be formed at least partially simultaneously by means of forming rollers generally designated 3. Each of the two ends is used for deformation 1b , 1c at least one forming roller 3 intended. In the embodiment according to the 3 and 4th are for reshaping the end 1b three forming rollers 3 and the end 1c a forming roller 3 indicated.

The forming rollers 3 are based on the longitudinal axis 4th the preform 1 , designed to be radially movable. Depending on the desired forming process, they can also be moved in the axial direction.

The spinning rollers are used during the forming process 3 compared to the workpiece holder 2 and the tubular preform 1 set in rotation so that either the pressure rollers 3 or the workpiece holder 2 with the preform 1 are driven.

Through the in the 3 and 4th The deformation shown is the two ends 1b and 1c the preform 1 deformed rotationally symmetrical, ie the two ends 1b and 1c then no longer have a polygonal cross-sectional shape if the original preform 1 had a polygonal cross-section. The polygonal cross-section naturally remains in the unprocessed central area 1a receive.

Starting from the already at both ends 1b and 1c reshaped tubular preform 1 can both ends 1b and 1c continue without changing the workpiece holder 2 be reshaped.

In 5 is shown that the two ends 1b and 1c viewed in the radial direction are each designed in two stages. This graded areas are in 5 With 1b ' , 1b " or. 1c ' , 1c " designated. Also is in the two ends 1b and 1c each introduced a profile, namely in the end 1b an inner profile 5 and to the end 1c an external profile 6th . The inner profiling 5 and the external profile 6th can be toothing, knurling or another geometric shape.

For creating the inner profile 5 or the outer profile 6th Suitable forming rollers are used as forming rollers and internal mandrels.

Another possible embodiment is shown in 8th shown. The preform 1 is unchanged in its central area 1a in the workpiece holder 2 held and in the already graduated end 1b is an inner mandrel 7th axially inserted without profiling while in the end 1c an inner mandrel 8th with external profiling 8a is introduced. To the embodiment after 8th at the end 1b the preform 1 an external profile 6th is to be introduced next to the inner mandrel 7th at least one forming roller 9 with an external profile 9a intended. To the other hand in the end 1c the preform 1 an inner profile 5 is to be introduced next to the inner mandrel 8th with external profiling 8a at least one forming roller 10 provided without external profiling, ie the end 1c is from the forming roller 10 into the outer profile 8a of the inner mandrel 8th pressed in so that the inner profile 5 arises.

In contrast to the embodiment according to 8th are in the embodiment according to 9 and 10 not two separate inner thorns 7th and 8th used, but the two inner mandrels 7 ' and 8th' are connected to one another at the end and / or in a form-fitting manner. The two inner mandrels point to this 7 ' and 8th' each has a complementary spur toothing 7a , 8a on. The inner thorns 7 ' and 8th' are then compressed in the axial direction during the deformation by the application of pressure on the outside, as a result of which lateral radial forces occurring during the deformation are intercepted.

It is also possible to use at least one of the two ends 1b , 1c the preform 1 to replenish metal material during the forming process (in the forming zone) when an axial force acts on the respective end 1b or. 1c is applied. This forming process is in the 11 and 12 shown. At least one forming roller is used 11 used, which has a step-shaped, tubular outer peripheral region with a circumferential contact surface 11a having. With this forming roller 11 is on the preform 1 an axial force F _axial and a radial force F _radial upset. This material tracking can also be repeated several times, for example before the actual deformation of the ends 1b , 1c and afterwards.

The entire manufacturing process can be done by cold forming alone. However, the deformation can also take place wholly or temporarily with the application of heat, for example by inductive heat generation. This can harden the preform at the same time 1 respectively.

List of reference symbols

1

Tubular preform

1a

Middle pipe area

1b, 1c

end up

1b ', 1c'

Graduated area

1b ", 1c"

Graduated area

2

Workpiece holder

3

Forming rollers

4th

Longitudinal axis

5

Internal profiling

6th

External profiling

7.7 '

Inner mandrel

8.8 '

Inner mandrel

8a

External profiling

8b

Spur gear

9

Forming roller

9a

External profiling

9b

Spur gear

10

Forming roller

11

Forming roller

F _axial

axial force

F _radial

radial force

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10337929 A1 [0002]

Claims (10)

Method for producing a hollow shaft from a tubular preform by spinning, wherein both ends of the preform are each formed with at least one forming roller, characterized in that a tubular preform (1) with any cross-section is used and the preform (1) is used during the entire manufacturing process up to is held by a workpiece holder (2) to the finished hollow shaft in the middle pipe area (1a). Procedure according to Claim 1 , characterized in that a tubular preform (1) with a polygonal cross-section is used. Procedure according to Claim 1 or 2 , characterized in that a drawn or welded preform (1) is used. Method according to one or more of the Claims 1 to 3 , characterized in that the two ends (1b, 1c) of the preform (1) are at least partially reshaped at the same time. Method according to one or more of the Claims 1 to 4th , characterized in that at least one end (1b, 1c) is stepped one or more times. Method according to one or more of the Claims 1 to 5 , characterized in that an outer and / or inner profile (5, 6) is introduced into at least one end (1b, 1c). Procedure according to Claim 6 , characterized in that an optionally profiled inner mandrel (7,7 ', 8,8') is axially inserted into the at least one end (1b, 1c) before the outer and / or inner profiling (5, 6) is introduced. Procedure according to Claim 7 , characterized in that an inner mandrel (7,7 ', 8,8') is inserted into both ends (1b, 1c). Procedure according to Claim 8 , characterized in that the two inner mandrels are connected to one another at the end with a force fit and / or a form fit. Method according to one or more of the Claims 1 to 9 , characterized in that the deformation takes place at least temporarily with the application of heat.

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